Control the transparency of a picture with Seekbar

<?xml version= "1.0" encoding= "Utf-8"? ><linearlayout xmlns:android= "Http://schemas.android.com/apk/res/android"Xmlns:tools= "Http://schemas.android.com/tools"Android:layout_width= "Match_parent"Android:layout_height= "Match_parent"Android:paddingbottom= "@dimen/activity_vertical_margin"Android:paddingleft= "@dimen/activity_horizontal_margin"Android:paddingright= "@dimen/activity_horizontal_margin"Android:paddingtop= "@dimen/activity_vertical_margin"Tools:context= "Com.hanqi.testapp2.TestActivity4"android:orientation= "Vertical" > <ProgressBar android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"style= "? Android:attr/progressbarstylehorizontal"android:progress= "0"android:secondaryprogress= "0"Android:max= "80"Android:id= "@+id/pb_1"/> <ProgressBar android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"style= "? Android:attr/progressbarstylelarge"Android:id= "@+id/pb_2"/> <SeekBar android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"android:progress= "0"Android:max= "80"android:secondaryprogress= "0"Android:id= "@+id/se_1"/> <Ratingbar android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"Android:numstars= "5"android:rating= "3.5"Android:isindicator= "true"/> <ImageView android:layout_width= "Wrap_content"Android:layout_height= "Wrap_content"android:src= "@drawable/xiao3"Android:alpha= "1"Android:id= "@+id/iv_1"/> <SeekBar android:layout_width= "Match_parent"Android:layout_height= "Wrap_content"android:progress= "0"android:secondaryprogress= "0"Android:max= "200"Android:id= "@+id/se_2"/></linearlayout>

 Packagecom.hanqi.testapp2;ImportAndroid.os.Bundle;Importandroid.support.v7.app.AppCompatActivity;ImportAndroid.util.Log;ImportAndroid.view.View;ImportAndroid.widget.ImageView;ImportAndroid.widget.ProgressBar;ImportAndroid.widget.SeekBar; Public classTestActivity4extendsappcompatactivity {SeekBar se_1;    ProgressBar pb_1;    ProgressBar pb_2;    SeekBar se_2;    ImageView iv_1; @Overrideprotected voidonCreate (Bundle savedinstancestate) {Super. OnCreate (savedinstancestate);        Setcontentview (R.LAYOUT.ACTIVITY_TEST4); Se_1=(SeekBar) Findviewbyid (r.id.se_1); Pb_1=(ProgressBar) Findviewbyid (r.id.pb_1); Pb_2=(ProgressBar) Findviewbyid (r.id.pb_2); Se_2=(SeekBar) Findviewbyid (r.id.se_2); Iv_1=(ImageView) Findviewbyid (r.id.iv_1); Iv_1.setalpha (0); //Alertdialog ad=new Alertdialog.builder (this). Create ();Se_1.setonseekbarchangelistener (NewSeekbar.onseekbarchangelistener () {//Progress Change Trigger@Override Public voidOnprogresschanged (SeekBar SeekBar,intProgressBooleanFromuser) {                //set progress value for progress bar 1pb_1.setprogress (progress); //determine if the maximum value is reached                if(progress==Se_1.getmax ()) {pb_2.setvisibility (view.invisible);//not displayed but the location is still reserved                }                Else{pb_2.setvisibility (view.visible); }                //as long as the progress change is triggered .//Toast.maketext (Testactivity4.this, "current progress =" +progress, Toast.length_short). Show ();} @Override Public voidOnstarttrackingtouch (SeekBar SeekBar) {LOG.E ("TAG", "progress bar start dragging"); } @Override Public voidOnstoptrackingtouch (SeekBar SeekBar) {LOG.E ("TAG", "Progress bar Stop dragging");        }        }); Se_2.setonseekbarchangelistener (NewSeekbar.onseekbarchangelistener () {@Override Public voidOnprogresschanged (SeekBar SeekBar,intProgressBooleanFromuser)            {Iv_1.setalpha (progress); } @Override Public voidOnstarttrackingtouch (SeekBar SeekBar) {LOG.E ("TAG", "progress bar start dragging"); } @Override Public voidOnstoptrackingtouch (SeekBar SeekBar) {LOG.E ("TAG", "Progress bar Stop dragging");    }        }); }}

Control the transparency of a picture with Seekbar